### NRICH PROBLEM SOLVING ANGLES

Given four of the angles in two triangles, can you find the smallest angle overall? Four rods are hinged at their ends to form a convex quadrilateral. What is the shaded area? What is the size of the marked angle? Estimating Angles Age 7 to 14 Challenge Level: Four rods, two of length a and two of length b, are linked to form a kite.

Be patient this problem may be slow to load. Weekly Problem 44 – Extend two of the sides of a nonagon to form an angle. The same spiropath is iterated. Input coordinates to help you search and find the giraffe in the fewest guesses. The linkage is moveable so that the angles change.

That is, they should all experience challenging, intellectually worthwhile and solfing mathematics. How would you turn at each nirch On a clock the three hands – the second, minute and hour hands – are on the same axis. Shogi tiles can form interesting shapes and patterns Cops and Robbers Age 7 to 16 Challenge Level: Weekly Problem 40 – Given three sides of a quadrilateral, what is the longest that the fourth side can be?

How long will it be before they are at right angles again? Register for our mailing list.

## Angle Hunt

You may need to do some estimating, some calculating and some research. Right Angles Age 11 to 14 Challenge Level: Stick some cubes together to make a cuboid.

Weekly Problem 1 – The diagram shows two circles enclosed in a rectangle. Pythagoras on a Sphere Age 16 soving 18 Challenge Level: If the shape on the inside is a rectangle, what can you say about the shape on the outside?

At the time of writing the hour and minute hands of my clock are at right angles. Geometry problems for inquiring primary learners. A triangle is shaded within a regular hexagon.

Sine and Cosine Age 14 to 16 Challenge Level: I was observing a lesson recently in which the teacher was showing her year seven class how to use a protractor. Olympic Turns Age 7 to 11 Challenge Level: Can you decide whether two lines are perpendicular or not? PQ has length 1. Weekly Problem 41 – Three straight lines divide an equilateral triangle into seven regions.

# Maths Search :

Can you work out their angles? Geometry Games Age 5 to 11 Challenge Level: Can you find the value of x in this diagram? The graph below is an oblique coordinate system based on 60 degree angles. An activity for high-attaining learners which involves solvihg a new cylinder from a cardboard tube.

Weekly Problem 45 – The diagram shows a regular pentagon with two of its diagonals.

# Angle Please :

Isosceles Prove that a triangle with sides of length 5, 5 and 6 has the same area as a triangle with sides of length 5, 5 and 8. Why does this fold create an angle of sixty degrees?

Age 7 to 11 Challenge Level: What is the relationship between the angle at the centre and the angles at the circumference, for angles which stand on the same arc?

Square Within a Square Within Explore the properties of isometric drawings.